This study is to define the maximum tolerated dose of paclitaxel and SDZ PSC 833 in patients with refractory solid tumor malignancies. After defining the maximum tolerated doses of these drugs in combination, it is envisioned that future studies will examine whether the addition of SDZ PSC 833, a cyclosporine analog which has been found in vitro and in vivo to reverse multidrug resistance, will reverse resistance in solid tumor malignancies.